The importance of collecting a "midstream" sample for urine analysis is well known but, despite a widely recognized need for a simple, effective, foolproof, single-use device that a patient might use with a minimum of instruction and without assistance, no prior device meeting all such requirements has previously been known. Quite typically, the devices proposed for midstream collection have been complex in structure and operation, in some cases involving moving parts which shift from one position to another as their balance is altered by collected fluid (U.S. Pat. Nos. 3,625,064; 3,830,107; 3,635,091). In other constructions, the so-called midstream sample is collected as a result of an overflow operation (U.S. Pat. Nos. 4,040,791; 3,943,770; 4,276,889). While some prior devices avoid the shortcomings of others, the need has nevertheless remained for a relatively simple device that has no serious defects or deficiencies in design and/or operation.